iscsi_sw_tcp_conn_set_param should check the pointer before using it. I got this ops when starting my os: [ 27.158355] sd 27:0:0:1: [sdco] Mode Sense: 83 00 00 08 [ 27.158377] scsi 27:0:0:3: Direct-Access ZBS VOLUME 0000 PQ: 0 ANSI: 5 [ 27.167665] connection39:0: detected conn error (1020) [ 27.174681] BUG: kernel NULL pointer dereference, address: 0000000000000020 [ 27.174706] #PF: supervisor read access in kernel mode [ 27.174719] #PF: error_code(0x0000) - not-present page [ 27.174731] PGD 0 P4D 0 [ 27.174739] Oops: 0000 [#1] SMP NOPTI [ 27.174749] CPU: 8 PID: 1044 Comm: iscsid Not tainted 5.11.12-300.fc34.x86_64 #1 [ 27.174767] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 12/12/2018 [ 27.174790] RIP: 0010:iscsi_sw_tcp_conn_set_param+0x6a/0x80 [iscsi_tcp] [ 27.174807] Code: 85 d2 74 23 48 89 83 e0 00 00 00 31 c0 5b 5d c3 e8 bb 21 fb ff 31 c0 5b 5d c3 48 89 ef 5b 48 89 d6 5d e9 99 62 ff ff 48 8b 03 <48> 8b 40 20 48 8b 80 a0 00 00 00 eb cd 66 0f 1f 84 00 00 00 00 00 [ 27.174847] RSP: 0018:ffffba8a46103b90 EFLAGS: 00010246 [ 27.174860] RAX: 0000000000000000 RBX: ffff98cbf22766b8 RCX: ffffffffc096d6b9 [ 27.174877] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff98cbdbcb6049 [ 27.174893] RBP: ffff98cbf2276348 R08: 00000000000000ff R09: 000000000000000a [ 27.174909] R10: 000000000000000a R11: f000000000000000 R12: ffff98cbdbcb6010 [ 27.174925] R13: ffff98cbdbcb6048 R14: ffff98cbf2279800 R15: 0000000000000414 [ 27.174941] FS: 00007fa88bab7cc0(0000) GS:ffff98d1e0000000(0000) knlGS:0000000000000000 [ 27.175188] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 27.175441] CR2: 0000000000000020 CR3: 000000022522c000 CR4: 00000000003506e0 [ 27.175734] Call Trace: [ 27.176003] iscsi_if_rx+0xdda/0x1adc [scsi_transport_iscsi] [ 27.176291] ? __kmalloc_node_track_caller+0xec/0x280 [ 27.176585] ? netlink_sendmsg+0x30c/0x440 [ 27.176880] netlink_unicast+0x1d3/0x2a0 [ 27.177191] netlink_sendmsg+0x22a/0x440 [ 27.177494] sock_sendmsg+0x5e/0x60 [ 27.177799] ____sys_sendmsg+0x22c/0x270 [ 27.178107] ? import_iovec+0x17/0x20 [ 27.178422] ? sendmsg_copy_msghdr+0x59/0x90 [ 27.178747] ? _copy_from_user+0x3c/0x80 [ 27.179072] ___sys_sendmsg+0x81/0xc0 [ 27.179402] ? ___sys_recvmsg+0x86/0xe0 [ 27.179736] ? handle_mm_fault+0x113f/0x1970 [ 27.180076] ? enqueue_hrtimer+0x32/0x70 [ 27.180422] __sys_sendmsg+0x49/0x80 [ 27.180778] do_syscall_64+0x33/0x40 [ 27.181132] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Signed-off-by: Li Feng <fengli@xxxxxxxxxx> --- drivers/scsi/iscsi_tcp.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c index 1bc37593c88f..2ec1405d272d 100644 --- a/drivers/scsi/iscsi_tcp.c +++ b/drivers/scsi/iscsi_tcp.c @@ -724,6 +724,8 @@ static int iscsi_sw_tcp_conn_set_param(struct iscsi_cls_conn *cls_conn, break; case ISCSI_PARAM_DATADGST_EN: iscsi_set_param(cls_conn, param, buf, buflen); + if (!tcp_sw_conn || !tcp_sw_conn->sock) + return -ENOTCONN; tcp_sw_conn->sendpage = conn->datadgst_en ? sock_no_sendpage : tcp_sw_conn->sock->ops->sendpage; break; -- 2.31.1
